Eta Sigma Phi

Eta Sigma Phi (ΗΣΦ) (ESP) is a College honor society which grew out of a local undergraduate classical club founded by a group of students in the Department of Greek at the University of Chicago in 1914. This organization later united with a similar organization at Northwestern University and became Phi Sigma. Phi Sigma was nationalized in 1924, and chapters were organized at leading colleges and universities.[1]  On May 14, 1927, it became Eta Sigma Phi, the National Honorary Classical Fraternity, and was incorporated under the laws of the State of Illinois. Though nominally a fraternity, as an honor society it is open to both genders.
See more at Wikipedia.org...